Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to a semiconductor device having a photoelectric conversion device and a method of manufacturing the same.
Description of the Background Art
In LSIs (Large Scale Integrated circuits) miniaturized and faster in recent years, copper having an electrical resistance lower than conventionally-used aluminum has been used as a material for forming wiring layers. Similarly, solid state image sensors such as CMOS (Complementary Metal Oxide Semiconductor) image sensors and semiconductor imaging devices including the same have been miniaturized and operating faster. In this respect, for example, Japanese Patent No. 4551603 and Japanese Patent No. 5367459 below disclose a solid state image sensor and a semiconductor imaging device using copper wiring.
When copper wiring is formed, in general, an integrated structure including a groove and a hole is formed in the interlayer insulating film as shown in Japanese Patent No. 4832807 below. The inside of the groove and the hole is filled with copper wiring. This results in a structure in which wiring is integrated with a connection portion for connecting the wiring with the underlying wiring. This dual damascene method is used when copper wiring is formed.
Copper wiring is disadvantageous in that its component tends to diffuse into the interlayer insulating film. In order to suppress this, a diffusion barrier film is formed in contact with the upper surface of copper wiring. The diffusion barrier film, however, has an opening region in the connection portion formed by the dual damascene method. This opening region is formed in order to electrically connect the wiring that overlies the diffusion barrier film with the underlying wiring. The diffusion barrier film also has an opening region immediately above a pixel region where a light-receiving element in a solid state image sensor is arranged. This opening region is formed in order to enhance the light-receiving property of the light-receiving element. For example, Japanese Patent Laying-Open No. 2008-199059 discloses a configuration in which a diffusion barrier film is removed both in the connection portion and in the region immediately above the light-receiving element.